A. Field of the Invention
The present invention relates to multi-tier wireless communications architecture, applications and methods of using wireless units having differing communication functionalities and ranges.
B. Description of the Related Art
Each year more electronic devices are being deployed in a wider variety of commercial areas. In particular, data acquisition devices, such as bar code scanners, hand held terminals and radio frequency identification (“RFID”) readers, are being adopted to speed up commercial operations and are a standard fixture in inventory tracking environments, as well as in many consumer businesses. With wide deployment of these electronic devices across manufacturing, inventory, and retail sales areas, there has been an increasingly strong demand for wireless connectivity between the data acquisition units and the corporate local area network (“LAN”). In response, various wireless solution vendors have come up with systems using spread spectrum technologies in the 900 MHz and 2.4 GHz radio bands. Spread spectrum technologies are widely used in these applications because they can co-exist with other radio devices without causing significant interferences and thus do not require FCC licenses. Various examples and details of spread spectrum communication in these radio bands using base stations, access points and portable terminals are disclosed in the following patents assigned to Symbol Technologies, all of which patents are herein incorporated by reference: U.S. Pat. No. 5,815,811; U.S. Pat. No. 5,812,589; U.S. Pat. No. 5,668,803; U.S. Pat. No. 5,528,621; U.S. Pat. No. 5,479,441; U.S. Pat. No. 5,418,812; U.S. Pat. No. 5,280,498; U.S. Pat. No. 5,157,687; U.S. Pat. No. 5,142,550; U.S. Pat. No. 5,103,461; and U.S. Pat. No. 5,029,183.
Although they have relatively long ranges and are versatile, these spread spectrum radio transceivers, however, have been generally expensive. Furthermore, due to the expensive nature of these radios, the applications have been generally limited to the more expensive data capture devices. However, cheaper and shorter-range radio transceivers, when used in conjunction with longer-range radios (collectively forming a “multi-tier radio communications architecture”), would have much broader applications heretofore unapplied, such as handheld terminals, price checkers, temperature and other sensors, hotel, school, and other door locks, and remote video cameras.
There also have been proposed multi-tier communication systems, such as the one disclosed in U.S. Pat. No. 5,790,536, which is herein incorporated by reference. U.S. Pat. No. 5,790,536 shows wireless units with relatively long range participating in the “premises” LAN and other wireless units with shorter range participating in the “peripheral” LAN. In such conventional systems the main communications are done through the “premises” LAN, whereas in the “peripheral” LAN, wireless units are temporally formed (and dissolved) on an ad hoc basis for short communications such as for printing. Furthermore, the conventional systems generally require a coordination between the upper-tier radio communication protocol and the lower-tier radio communication protocol. These factors (i.e., need to accommodate ad hoc communications and protocol coordination between different tier units) generally contribute to a more expensive solution for the lower-tier radio transceiver. Moreover, U.S. Pat. No. 5,790,536 discloses only a few specific applications and does not disclose detailed applications of the multi-tier architecture discussed hereinbelow.